Hammer-drill.



W. 'PRELLWITZ.

HAMMER DRILL.

APPLICATION FILED AUG.19. 1909.

Patented Mar. 28, 191T.

Wwaaea= UNITED STATES PATENT OFFICE.

WILLIAM PRELLWITZ, OF EASTON, PENNSYLVANIA, ASSIGNOR TO ING-ERSOLL-BANDCOMPANY, OF NEW YORK, N. Y., CORPORATION OF NEW JERSEY.

HAMMER-DRILL.

Application filed. August 19, 1909. Serial No. 513,684.

To all whom it may concern:

Be it known that I, WILLIAM PmiLLwrrz, a citizen of the United States,and resident of Easton, in the county of Northampton and State ofPennsylvania, have invented a new and useful Improvement in Hammerl)rills, of which the following is a specification.

This invention relates to hammer drills and has for its principal objectto provide a very simple and inexpensive attachment for the drill, whichmay be readily brought into and out of position for use as a retainerfor limiting the outward movement of the drill steel when it is notstriking its work.

In the accompanying drawings, Figure 1 represents the front portion of ahammer drill in top plan. with my tool retainer-applied thereto in its 0erative position, the type of drill shown belng that in which the steeldoes not rotate with respect to the drill,

Fig. 2 is a cross section taken in the plane of the line AA of Fig. 1,looking in the direction of the arrows, Fig. 3 represents the frontportion of the hammer drill shown in Fig. 1, in side elevatidn with mytool retainer applied thereto in its operative "position, theinoperative position of the retainer being shown in dotted lines, Fig. 4is a longitudinal central section taken in the plane of the line BB ofFig. 3, looking in the direction of the arrows, and Fig. '5 representsthe front portion of a hammer drill in top plan with my tool retainerapplied thereto in its operative position, the drill shown in thisfigure being of thetype in which the drill steel rotates.

In the form shown in Figs. 1130.4;1110111- sive, the drill cylinder isdenoted by 1, it's hammer piston by 2, its drill steel by 3 and thedrill steel chuck by' l. The drill steel is provided with two oppositelyarranged elongated transverse recesses 5,. 6, located adj acent to thechuck 4. The cylinder 1 is provided with two diametrically opposed holes7, 8, for receiving the inwardly turned ends 9, 10, of the side arms 11,12, of the'retainer, for pivoting the retainer to the cylinder.

. The cylinder 1 is further provided with diametrically opposed recesses13, let, in front of andin almement'with the holes 7, 8,. for receivingoffset portions 15, 16,"in the side arms ll, 12, of the retainer. Thelaterally arranged connecting portion at the} outer ends. of the sidearms 11,12, is bent to form a yoke 17, the sides 18,19, of which, whenthe device is in its operative position, are fitted to embrace the drillsteel 3 within the elongated transverse recesses 5, 6, at the outer endsof said recesses so as not to interfere with the operation of the steelunder the impact of the hammer piston 2.

In the form shown in Fig. 5, where the drill steel is rotatable withrespect to the drill cylinder 1, the steel is provided with aSpecification of Letters Patent. Patented Mar. 28, 1911..

circumferential shoulder 20 adjacent to the chuck i and the yoke 17 isbrought into en-' gagement with the steel at a point spaced from theshoulder 20 when the retainer is in its operative position. Thisretainer is formed from av single strip of spring wire, the'tension onthe side arms 11 and 12 being such as .to tend to force them together sothat when the retainer is swung into its operative position, the offsetportions 15, 16, of the side arms 11 and 12 W111 snap into the recesses13, 14, for yieldingly holding the retainer in its operative position.This spring tension also serves to hold the inwardly turined ends 9 and10 within their holes 7 an 8.

In operation, when the drill is in use, the

retainer may be swung out of its operative position. When the operatorwishes to withdrawthe drill steel partially or wholly from the hole, as,for instance, for the purpose of permitting the material to be blown outof the steel, wherea hollow steel is used,

insertion and removal of the drill steel is provided for.

While Ihave shown and described this retainer in connection with ahammer drill,

it is to be understood that it could be used equally well in connectionwith tools of variousother types without departing from the spirit andscope of my invention, thegist of which is toprovide a novel, simple andposition with respect to its holder when the tool is not in use. I

What I claim is inexpensive retainer forret-aining a tool in 1. A toolsteel, its holder and a tool steel eeaoee retainer comprising a wirebent to form a yoke for embracing the'steel and side arms pivoted to theholder.

2. A tool cylinder, a tool steel and a tool steel retainer comprising aWire bent to form a yoke for embracing thesteel and spring side armspivoted to the cylinder, the cylinder and retainer being constructed toyieldingly hold the retainer in its operative position.

3. A toolcylinder having diametrically opposed holes and recesses, atool steel and a tool steel retainer comprising a wire bent to form ayoke for embracing the steel and side arms having inwardly turned endslocated in said holes and ofiset portions for entering said recesses toyieldingly hold the retainer in its operative position.

I. As an article of manufacture, a tool steel retainer comprising a wirebent to form side arms and a laterally arranged tool steel embracingyoke connecting the outer ends of the side arms.

5. As an article of manufacture, a tool steel retainer comprising a wirebent to form side arms and a laterally arranged tool steel embracingyoke connecting the outer ends of the side arms, the inner ends of theside arms being turned inwardly to form pivots.

6. As an article of manufacture, a tool steel retainer comprising a wirebent to form side arms and a laterally arranged tool steel embracingyoke connecting the outer ends of the side arms, the inner ends of theside arms being turned inwardly to form pivots,

the said side arms having offset portions thereon to form yieldingstops.

7. A- tool cylinder, a tool steel having a recessed portion, and a toolsteel retainer comprising a yoke for embracing the steel at 40 therecessed portion, and side arms pivoted to the cylinder.

, In testimony, that I claim the foregoing as my invention, I havesigned my name in presence of two witnesses, this sixteenth day

